I am stuck with a 2008 GT AWD (bought in April-08) and it is exhibiting a "harmonic vibration" throughout the car at highway speeds. It is worst between 55 and 80 mph. It is still noticeable at any speed above about 45 mph. After 300 miles on the interstate, I feel like I'm sitting on a massage seat and then it gets worse like a paint-shaker

Dealer has tried:

• Tire rotate and balance - multiple times with force balancing, nothing odd found... no help.
• 4-wheel alignment – no change, but it was fairly far out of spec after only 1,500 miles
• Replacing the tail-shaft – very minor improvement. Note they did NOT issue a TSB on this but admitted it is a known problem.
• "Special Lube" in the rear differential - no change.
• Some form of elaborate balancing on the tail-shaft – no real change

I have tried simulating the RPMs in different gears and the vibe only appears at highway speeds not highway RPMs. So, it’s not the motor itself.

So, I asked Mazda to trade with me for a new car of the same type. They came back and said that putting me in a new car would not solve the problem. That the vibration was “normal” in their opinion.

I asked them for a refund… gee, what a surprise that they would say NO.

So, I will pursue the Lemon Law and other legal action. Texas Lemon Law was written by the car dealers (gotta love Texas politics) and you have almost no protection. We’ll see how far I get but I may be stuck with a LEMON!!

Bottom line, Mazda knows the car has this vibration issue. After testing/identifying FOUR units that all exhibit the vibration they could not cure it and have concluded it is “as designed”. Let me tell you, I have test driven almost all the CUVs out there and NONE vibrate like this. It is NOT normal!

If you own a CX-7 AWD you may have this defect and not realize it... yet.
The vibration is evident at all speeds over about 45 mph but most evident at 65 to 75 mph. The kicker is if you typically drive less than a couple hours non-stop you may not have experienced the true problem. Once the vehicle has been driven for several hours non-stop the vibration escalates dramatically until it is almost unbearable. As if you had a square tire.

So, if you own an AWD and you sense any constant vibration on smooth roads at highway speeds, you have the issue. And, I'd like to ask for some help. I'd like you to reply to this post so I can determine if there are enough of us out there to qualify for a Class Action Suit. Mazda already admitted to finding one more like mine and I found two. Lawsuits are not fun so, hopefully, I can make Mazda aware of enough other cases that it will be an incentive to realize they can't ignore this issue.

So, it appears they have me where they want me for now... they got my money and they are NOT going to fix the problem. A case of the big corporation showing what they really think of the customer. I am truly glad that Mazda does not make heart defibrillators!!

This is my first and LAST Mazda… they are NOT planning on fixing this so BEWARE!!

 

I am truly sorry for your trouble, Maavalous, and would be pissed off/disenchanted too. I wonder though, has anyone tried replacing the tires?
I ask because I once had a girlfriend w/a Honda Civic. I thought it was the worst car in the world and chased everything I could think of for 2 yrs. Brakes, tire balance, tire rotation, alignment, bushings, shocks and ball joints. Even the manual steering rack was suspect, until the tires finally wore out and we had to replace them. Suddenly it was a whole different car!!
The end of the story is that I bought the car from her several yrs later, drove it, modified it, raced it and loved it for another 100K+ miles, until it literally rusted out from under me. I think I still love that car better than my Mazda3 now, but it is a close toss-up.
The car had an out of round tire that was causing all the trouble. It's rare they get by the factory like that, and sometimes if the tire is manufactured w/a defect the problem only shows up some time later. Very hard to diagnose, but easy to fix.
I'm thinking that it just might be your problem too?

 

Hey Virgin1

Nope, they took the tires/wheels to a performance tire shop. Had them tested for round (better than mfr. spec), had the wheels balanced and then had the mounted set force-balanced (the only way to go, by the way).
Then, I did similar tests on my own just to be sure they weren't lying.

There are 3 parts in an AWD that are different from the FWD...
A Power Take-Off (PTO) on the front transaxle
A 3-piece tail shaft
An hydraulic rear differential.

That's it. NO electronics or anything "cool". Just a dumb unit that grabs when things spin

The only thing I didn't investigate already is the front windsheild

It's a HUGE manufacturer's defect and they are lying about it

 

Interesting see my post in truck section.

 

Yep... NoWayJack... looks like the vibration problem may be across more models than I thought. I wonder about CX-9 as well... probably using the same bits across a lot of models. I think they are doing something different in the "truck" lines than the cars (like the mazdaspeed6) but can't find good info on that.
I really think the culpret is the rear differential... or, most likely, the clutch mechanism on the rear dif. But, until Mazda decides it is not "normal" I can't get them to work on it any further

 

Same here, 2007 CX-7, 60 mph and up extreme road noise w/vibration, wheel bearings (all) changed out in last couple years, new good tires 500 miles ago also.

 

Mazda and AWD doesn't really mix, especially in larger vehicles. I think the Mazdaspeed 6 was OK, but not even the CX-5 overall. Think Mazda hasn't had enough experience with AWD in larger SUV vehicles, even CUV.
Want AWD, but a Subaru! Subaru has the experience!

 

It's a wheel bearing. They're $400-$500 to fix per wheel.

Mystery solved.